Back to results
US 6,603,934 B2Granted
Method and apparatus for forming image
AssigneesKabushiki Kaisha Toshiba, Toshiba Tec Kabushiki Kaisha
InventorShoko Shimmura
Life of this patent
Estimating the term…
Abstract
The present invention employs a thickness detecting mechanism including a system for emitting polarized light and a reception system for receiving reflected light and generating electric signals. By use of this thickness detecting mechanism, the thickness of a toner layer attached to a latent image is measured. Developing conditions are controlled in relation to the measured thickness.
Claims16
An electrophotographic developing apparatus which develops a latent image on a photosensitive body by use of a toner liquid in which toner is dispersed in a non-polarity solvent and which forms a toner image on the photosensitive body, said electrophotographic developing apparatus comprising:
- a photosensitive body which holds an electrostatic image;
- a charging unit which provides the photosensitive body with a predetermined potential;
- an exposure unit which forms an electrostatic image on the photosensitive body;
- a developing unit which includes a developing roller opposing the photosensitive body with a predetermined gap maintained, and which supplies a toner liquid to the electrostatic image formed on the photosensitive body such that toner is selectively attached to the electrostatic image, thereby forming a toner image;
- a developing bias source which applies a predetermined bias voltage to the developing unit;
- a toner layer thickness-detecting mechanism which detects the thickness of toner constituting the toner image, said toner layer thickness-detecting mechanism including an emission system which emits polarized light toward the toner image formed by the developing unit, and a reception system which receives the polarized light reflected by the toner image and produces an electric signal;
- an image formation condition-controlling device which controls at least one of an output from the charging unit, an output from the exposure unit and the bias voltage applied by the developing bias source, on the basis of the thickness of the toner layer detected by the toner layer thickness-detecting mechanism;
- and
- a toner liquid replenishment mechanism which supplies the developing unit with a toner liquid whose toner density is a predetermined value, said toner density being a ratio representing how much the toner is dispersed in the non-polarity solvent.
6 more elements
An electrophotographic developing method which develops a latent image on a photosensitive body by use of a toner liquid in which toner is dispersed in a non-polarity solvent and which thereby forms a toner image on the photosensitive body, the electrophotographic developing method comprising:
- providing the photosensitive body with a predetermined potential;
- forming a test image by exposure by use of an exposure unit;
- forming a toner layer on the photosensitive body by developing the test image;
- irradiating the toner layer with polarized light and measuring the thickness of the toner layer on the basis of reflected light reflected by the toner layer by use of a layer thickness-detecting mechanism, said toner layer thickness-detecting mechanism including an emission system which emits polarized light and a reception system which receives the reflected light and produces an electric signal;
- and
- comparing the thickness of the toner layer with a reference value and varying at least one of the potential provided for the photosensitive body, an intensity of exposure light output from the exposure unit, a toner density of the toner liquid and a developing bias voltage applied to a developing unit, wherein toner liquid replenishment is executed when the thickness of the toner layer is less than a predetermined value and the toner density of the toner liquid is within an allowable range.
3 more elements
A method which is based on subtractive primaries and forms a color image by using first-color toner, second-color toner and third-color toner, which produce first to third complementary colors to three primary colors and by further using seventh-color toner which emphasizes black, the method comprising:
- rotating a photosensitive body at a predetermined rate;
- charging the photosensitive body, which is capable of holding an electrostatic image thereon, to a predetermined potential that enables formation of a first-color toner image;
- irradiating the photosensitive body with light corresponding to image data used for forming the first-color toner image;
- forming the first-color toner image by supplying the first-color toner to an electrostatic image corresponding to the first-color toner image;
- charging the photosensitive body, which is capable of holding an electrostatic image thereon, to a predetermined potential that enables formation of both a second-color toner image and a fourth-color toner image, the fourth-color toner image being an image obtained by superposing the first-color toner and the second-color toner;
- irradiating the photosensitive body with light corresponding to image data used for forming the second-color toner image and the fourth-color toner image;
- forming the second-color toner image and the fourth-color toner image by supplying the second-color toner to electrostatic images corresponding to the second-color toner image and the fourth-color toner image;
- charging the photosensitive body, which is capable of holding an electrostatic image thereon, to a predetermined potential that enables formation of a third-color toner image, a fifth-color toner image and a sixth-color toner image, the fifth toner image being an image obtained by superposing the second-color toner and the third-color toner, and the sixth-color toner image being an image obtained by superposing the first-color toner and the third-color toner;
- irradiating the photosensitive body with light corresponding to image data used for forming the third-color toner image, the fifth-color toner image and the sixth-color toner image;
- forming the second-color toner image, the fifth-color toner image and the sixth-color toner image by supplying the second-color toner to electrostatic images corresponding to the second-color toner image, the fifth-color toner image and the sixth-color toner image;
- charging the photosensitive body, which is capable of holding an electrostatic image thereon, to a predetermined potential that enables formation of a seventh-color toner image, the seventh-color toner image being formed without reference to an order in which the first to the sixth-color toner images are formed;
- irradiating the photosensitive body with light corresponding to image data used for forming the seventh-color toner image;
- forming the seventh-color toner image by supplying the seventh-color toner to an electrostatic image corresponding to the seventh-color toner image;
- detecting the thickness of each toner layer of each of the toner images by use of a toner layer thickness-detecting device in a state where the photosensitive body is rotating, said toner layer thickness-detecting device including an emission system which emits polarized light toward each of the toner images, and a reception system which receives the polarized light reflected by each toner image and produces an electric signal;
- comparing the thickness of each of the toner layers of each of the toner images with a reference value;
- and
- varying at least one of a potential provided for the photosensitive body to obtain a desired image, the amount of light output from an exposure unit to obtain the desired toner image, a toner density of a given toner liquid and a developing bias voltage applied to a developing unit containing the given toner liquid, in accordance with a result of comparison.
14 more elements
Dependencies are inferred from the claim text.